Synergists to aerosol insecticides



Patented 4, 1944 2,345,891 SYNERGISTS 'ro AEROSOL INSECTICIDES WilliamN. Sullivan,

Washington, D. 0., and Lyle D. Goodhue, Berwyn, Md., asslgnors to ClaudeR. Wlckard, as Secretary United States of America,

in oillce of Agriculture 01' the and to his successors No Drawing.Application September 30, 1941,

Serial No.

5 Claims. (01. low-22) (Granted under the act of March 3, 183, asamended April 30, 1928; 370 0. G. 757) This application is made underthe act of March 3, 1833, as amended by the act of April 30, 1928, andthe invention herein described and claimed, if patented, may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment to us of anyroyalty thereon.

Our invention relates to materials which will increase the effectivenessof insecticides in aero-' sol form.

Certain agents which may or may not be toxic in themselves when added toaerosol insecticides greatly increase the rate of mortality. Theincreased toxicity obtained by the combination of such materials isoften referred to as "synergism and the added material a synergist.,Therefore, in these terms, the general object of our invention is theprovision or materials suitable as synergists for aerosol insecticides.7

Another object of our invention is the proviof fatty acids and ethyleneor propylene glycol, of glycerine or sorbitol, to be especially suitableas well as fatty acids in combination with amines such as methanolamine,sulfonated aryl and alkyl radicals alone or combined with an amine.

There are many processes which can be used to apply these materials inthe form of aerosols, such as spraying into the atmosphere,vaporization, by chemical reaction, by spraying on a heated surface, andso forth. Although this invention is not limited to any particularmethod of application, our preferred method of application comprisesdissolving the synergist in the insecticide, if the insecticide is aliquid, or dissolving it in some solvent common to both if a solid, and

. praying the solution on a heated surface, wheresion of agents whichwill notonly increase the I insecticidal action of materials known topossess some toxicity, but, which will also impart insecticidalproperties to materials which are known to be non-toxic or to have avery low toxicity.

A further object of our invention is the provision of such agents actingas synergists, which can be applied by dispersion simultaneously withand by the same methods used for the preparation of aerosolinsecticides.

We have found that materials suitable for the purposes of-this inventionbelong most frequently to the class of chemical compounds which aresurface active in non-aqueous solvents or which act as detergents innon-aqueous solvents. These compounds, in general, contain polargroupings such as the hydroxyl, the carboxyl, the amine, the ammonium,or the sulionic acid, alone, in multiple, or in combination, which isattached to some long chain aliphatic radical, or, in some cases; anaromatic radical.

Substances-acting as detergents or surface active agents in non-aqueousmedia can be easily applied by the usual methods of aerosol production,but this invention is not limited to these substances because differentmethods of. aerosol production can be used with diiferent types ofsynergists. Inthis class of chemical compounds we have found the fattyacids, the mono esters ergists in accordance with -zene per 1000 cu. it.gave only a 2% by an aerosol is formed composed of both the synergistand the insecticide.

A synergist to an insecticide in aerosol form is not necessarily also asynergist to an insecticide in spray form, even of the same compound.Ac-' tual tests have disclosed that an agent which possesses little orno effect as a synergist to an insecticidal spray may be extremelyeffectiveas a. synergist to an insecticidal aerosol. The reason for thisis not apparent, but it would seem that the mere wetting of the insectcannot explain the action.

The following results were obtained using syn. this invention. Theseresults were obtained on the basis of preliminary tests first carriedout in a small chamber of 7 cu. ft. and then on a larger scale in a 216cu. ft. chamber. In each test from 500 to 600 flies were used.Six-tenths of a pound oi o-dichlorobenkill. However, when mixed with0.16 lb. of oleic acid as a synergist, a kill was obtained. This samequantity of oleic acid, when used alone under the same conditions gaveonly a 1% kill. Laurie acid when used alone in the same amount, namely,0.16 lb. per 1000 cu. i't., gave only a 1% kill, but when used as asynergist with 0.6 lb. of o-dichlorobenzene per 1000 cu. it. a kill wasobtained.

The same synergists were testedv at other concentrations and it wasfound that little is gained by adding more than 10%.

The i'ollowing is a list of substances which were tested as synerl atsat a concentration 0! plus oleic acid, ethyl 0.06 lb. in 0.6 lb. ofo-dichlorobenzene per 1000 cu. it. against the housefly, the percentageof kill in each case being indicated in the right hand column:

. Per cent kill Spermaceti 37 Diglycol laurate 43 Sulfonated naphthalene60 Salicylic acid 91 Propylene glycol oleate 28' Myristic acid 49Propylene glycol laurate '74 Sorbitol laurate 59 Monoglycol laurate 56Triethanolamine oleate 56 Lauryl sulfate 70 chloroethane plus lauricacid, and o-dichlorobenzene plus lauric acid. In all cases where oleicacid was efiective, lauric acid was also found to be effective and viceversa. The kill without a synergist was always less than 100% andusually less than 50%.

In a 1100 cu. ft. room, naturally infested with cockroaches, more than5000 were killed in 18 hours and none were found living, using 1 /2lbs.-

of o-dichlorobenzene with 3% lauric acid and p 2% oleic acid. Excellentresults were also obtafned in a 3200 cu. ft. room.

Tests were also conducted against the carpet beetle larva, the confusedflour beetles and crickets. The halogenated esters in combination withany oneof the synergists mentioned above is extremely toxic to theconfused flour beetle and produces a high mortality to the carpet beetlelarva.

Among compounds tested against the housefly in the form of aerosols, incombination with synergists of the type mentioned above are,3-chloroacenaphthene, z-chlorofluorene, 3-chlorodibenzofuran,chlorinated diphenyls, halogenated naphthalenes, halogenated esters,halogenated ketones, carbazole, thiocresol and halogenated phenols. Thesynergist was'shown to be responsible in each case for an increase intoxiclty.

Having thus described our invention, we claim:

1. An insecticide in aerosol i'orm comprising ortho-dichlorobenzene andlauric acid.

2. An insecticide in aerosol form comprising a solution containingessentially 99.9 to parts by weight of ortho-dichlorobenzene and 0.1 to10 parts by weight of lauric acid.

3. An insecticide in aerosol form comprising ortho-dichlorobenzene andoleicacid.

4. An insecticide in aerosol form: comprising a solution containingessentially 99.9 to 90 parts by weight of ortho-dichlorobenzene and 0.1to 10 parts by weight of oleic acid.

5. An insecticide in aerosol form comprising ortho-dichlorobenzene andmyristic acid.

WILLIAM N. SULLIVAN. LYLE D. GOODHUE.

